Plasticized gelating compositions



atent 3,033,680 PLASTICIZED GELATIN COMPOSITIONS I Kirby M. Milton and Fred W. Spengler, Rochester, N.Y.,

This invention relates to plasticized gelatin compositions such as gelatin coating compositions or photographic emulsions in which an ether-ester or a diester of an alkylene glycol or of a poly(alkylene glycol) is used as the plasticizer.

Gelatin coatings on supports, for example, silver halidegelatin emulsion layers often tend to crack when flexed, especially at low humidities. Various materials have been suggested for incorporation in gelatin coatings to improve the flexibility characteristics thereof, but most of these exhibit disadvantages of one kind or another.

-One object of our invention is to provide plasticized gelatin compositions. Another object of our invention is to plasticize gelatin layers Without imparting excessive softness or tackiness to them under high humidity and high temperature conditions, as is often the case with commonly known plasticizers. A further object of our invention is to prepare gelatin coating compositions containing as the plasticizer therein an ether-ester or a diester of an alkylene glycol or of a poly(alkylene glycol).

We have found that by the incorporation of 530% based on the weight of the gelatin of an ester-ether or a diester derivative of an alkylene glycol or of a poly(alkylene glycol), that compositions are obtained which coat out in the form of layers that have good flexibility graphic emulsions were prepared as follows: 1) Aqueous solutions containing 8% of photographic gelatin and the indicated percentage of plasticizer were coated on siliconetreated glass plates in such volume that dried thicknesses of 4 mils were obtained. The sheets were cured at 70 F., and 70% relative humidity until dry. They were then stripped from the plates, slit to widths of 15 mm. and conditioned to 70 F., 20% relative humidity. Their folding endurance was tested with an MIT fold tester using a tension of 1 kg. and jaws of 0.0155 inch radius of curvature with a separation of 0.01 inch. (2) Sheets of silver halide emulsions, similarly plasticized, were pre- 3 Increase in Example 2 Sheets were prepared in the same manner as in the preceding example but using varied concentrations of methoxy triglycol acetate. The results obtained were as follows: i

Example 1 7 Thin sheets of gelatin and of silver halide-gelatin photocharacteristics and are free of excessive softness and tackimess. The materials which are useful for plasticizing MIT f ld at W F" z y 207 R.H, gelatin are those having the formula Percent PM 01m 0 H Gelatin Emulsion R1 0 R2) 1.0-0 -R;; sheets sheets in which R =alkyl, acyl, or alkoxyacyl, R =alkylene, 24 R '=alkyl or alkoxy alkyl, and n=a simple integer from. f 5 24 g: 1 to 8. lg 41 112 Some compounds which have been found to be good 20 2g plasticizers and the R R R and n values thereof are 45 20 49 54 as follows:

Ri' Ra Ra. 2-methoxyethyl acetate, i.e., methyl Cellosolve acetate CH3- CH2CH2- OHs- 1 2-ethoxycthyl acetate, i.e., Cellosolve acetate CzHs- OHZOH9- CH 1 2-(2-methoxyethoxy)ethyl acetate, i.c. methyl Carbitol acetate OH3- -OHzCHg CH3 2 2-(2-ethoxyethoxy)ethyl acetate, i.e., arbitol ace C2Hfl' -GH2GH CH3- 2 2-(2-butoxyethoxy)ethyl acetate, i.e., butyl Garbitol acetate 0 119- OH OH CH 2 2-(2-(Z-mcthoxyethoxy)ethoxy)ethyl acetate i.e., methoxy triglycpl acetate GH3 CHzOHz- GH 3 2-(2-(2-ethoxycthox3 ')ethoxy)ethyl acetate, l.e., ethoxy trlglycol acetate C2H5- -OH2GH2 CH3- 3 2-(2-methoxyethoxy-ethyl propionate, i.e., methyl Carhitol propi0nate 0H3- CH2CHz- C2H5 2 Glycol diacetate CH3CO -CHOH; OH3 1 Triethylene glycol diacetate 1 OHBCO ---CHzCHz- CH 3 Triethylene glycol diprop (3211500 OH2OH: O H 3 2-(2-methoxyethoxy)ethyl methoxyacetate, l.e., methyl Carbltol methoxyacetate 0H3- 0H2CH:- CH OOH 2 i I 0H3 2-methoxypropyl acetate, i.e., methoxy propylene glycol acetate OHI- OH OH- OH;- 1

' 2-(2-methoxypropoxy)propyl acetate, 1.0., methoxy dipropylene glycol acetate v CH3- -OH;OH 0H 2 Z-(Z-(Z-methoxypropoxy)propoxy)propyl acetate l.e., methoxy tripropylene glycol acetate-.. OH;- OHzOHz- OH:- 3

The following examples illustrate the invention:

Example 3 Sheets were prepared and tested in the samemanner as in Example 1 but using diesters as the plasticizers, instead and dried at the highest possible temperature without reof the ether-ester of Example 1. I'he results obtained melting. The following results were obtained:

Tackiness Brittleness, 70 F.,

15% RH sward Coefficient of friction Percent Plasticizer rocker, 70 F., (emulsion to emulsion) 80% RH, Damping Wedge 1 MIT time, sec. 70 1"., 70 F., increase Folds 50% RH 70% RH None 0 23 0 49 0 47 0.44 10 Methoxy Triglycol Acet 0 10 12 45 0 49 0.44 20 --d0-- 0 11 17 45 0 46 0. 49 20 Glycerin 0 29 6 23 0 52 0.82

l Decrease in wedgebrittleness values indicates an increase in flegribility. I B A decrease in sward rocker time and an increase in coefficient of friction indicate increase in tackmess and/or softness were as follows:

MIT folds at 70 F., 25% RH. Percent Plastioizer 25 Gelatin Emulsion sheets sheets E l xamp e 0 None 24 1 4 2g c %1 }iacetr te Another series of coatlngs was prepared and evaluated 2 e y ene g yco ace a e 2o methylene glycol 55 0 as described in Example 4. The results obtained were as follows:

Tackiness Brittleness, 70 F.,

Sward Coeflicient of friction Percent Plasticizer t roglgfiggl, (emulsion to emulsion) 'dai nping' V I Wedge MIT time, sec. 70 F., 70 F., increase folds 50% RH 70% RE 0 None 0.20 1 1 49 0. 45 0.48 20 Methoxy Triglycol Acetate"- 0.10 19 45 0.88 0. 47 20 Glycerin 0.15 15 27 0. 40 0.80

50 Example 6 Example 4 p 7 Another series of coatings was prepared in a manner A negative-type silver halide-gelatin photographic emulsimilar to that of the preceding examples using a photosion was used to prepare sheets having plasticizer congraphic emulsion, the concentration of methoxy triglycol acetate having been varied. The results were as follows:

Teckiness Brittleness, 70 F.,

Sward Coefiiclent of friction Percent Plasticizer rocker, 70F., (emulsion to emulsion) damping Wedge MIT time, sec. 70 F., 70 increase folds 50% RH 70% RE tents of the kind and proportion as indicated below. Th1s Example 7 emulsion was coated onto'a-cellulose acetate support Anegative-type silver halidegelatin photographic emul- 5 sion was used to prepare a variety of coatings, the compositions being indicated below. After these emulsion compositions were prepared, they were coated onto cellulose acetate support and dried at the highest possible temperature. The results obtained were as follows:

In the various cases above, the plasticizer was added directly to the gelatin coating composition prior to its use in a coating operation. However, it is to be understood that other means may be used to incorporate the 5 plasticizer in the gelatin. For instance, the plasticizer Brittleness Tackiness and/or softness (15% RH, 70 F.) 7

Percent Plastieizer Sward rocker Coefficient of Ferrotyping 1 Wedge MIT 80% RH, 70 friction metal rating increase folds F., damping to emuL, 70% 7 days at time, sec. RH, 70 F. 120 F None; 0. 27 0 52 0. 21 2-3 20 Methyl Oellosolve acetate 0.31 0 50 0.23 1 20 Cellosolve acetate 0.20 11 53 0. 21 1 20 Methyl Oarbitol acetate--- 0. 09 15 50 0.33 3 20 Oarbltol acetate 0.14 17 52 0. 34 2 20 Butyl Oarbitol acetate... 0. 24 3 52 0.36 2 20 Methoxy triglycol acetate 0. 12 20 47 0. 29 2 20 Glycerin 0. 21 14 31 0. 69 5 Ferrotyping was rated from 0 (none) to 6 (complete) and is a measure of the tendency of the emulsion to soften and flow under conditions of test.

Example 8 Another set of coatings was prepared and evaluated. in 30 a similar manner, using a gelatin-silver halide photographic emulsion, the compositions being indicated below. The results obtained were as follows:

may be imbibed from a solution by the gelatin layer or ,by contacting the gelatin layer with another layer containing the plasticizer under such conditions that the plasticizer will migrate into the gelatin layer. The following examples illustrate imbibing plasticizer from solution:

. Example 10 An unplasticized negative-type photographic emulsion Brittleness, RH, 70 F Sward rocker, Coefl'icient of Ferrctyping Percent Plastlcizer 70 friction, metal rating (raw;

' F., damping to emu1., 70% 70% RH), Wedge MIT time, sec. RH, 70 F. 7 days at increase folds 100 F 0 None 0. 21 0 43 0. 26 1-2 Methyl Oarbitol acetate 0- 07 21' Y 0. 29 3-4 .20 Methoxy triglycol acetate- 0.08 23 38 0.28 3 20 Ethoxy triglycol acetate--- 0. 11 23 39 0. 36 5 20 Methyl Oarbitol propionate 0. 11 16 4O 0. 28 2 20 Methyl Garbitol methoxyacetate 0. 07 22 40 0. 29 1 20 Methoxy propylene glycol acetate 0.25 0 42 0. 21 p 3 20 Methoxy dipropylene gylcol acetate 0.20 5 40 0.33 5 20 Glycerin 0.26 0 23 v 1. 06 4 Example 9 Samples of a negative-type silver halide-gelatin photowas coated out in the form of raw film. Samples of this graphic emulsion were plasticized with the compounds and in the amounts indicated below, coated onto cellulose acetate support, and dried at the highest possible temperature. The coatings obtained were evaluated and the following results were obtained:

raw film were brought into contact with 2% aqueous solution of plasticizer as indicated at 70 F. for 1% minutes passed through rubber wringer rollers to remove any surface liquid and dried for 1 minute at 200 F. The

Brlttleness, F., Tackiness and/or softness P cent' Plastieizer Sward Coeflicient Ferrotyping er Wedge MIT rating, of friction (60% RH) increase folds 70 F., a (metal to 7 days at RH emul.) 70 F., F.

0 None 0.27 0 52 0.21 2-3 V 20 ,Glycol diacetate- 0.30 0 53 0.25 2 20 Triethylene glyco 0. 21 12 50 0. 33 7 23 20 'lriethylene glycol dipropiona 0.25 1 52 0.31 2-3 20 Glycerin 0. 21 14 31 0. 69 E brittleness of the films was evaluated and the following results were obtained:

8 alkylene glycol derivatives, including the plasticizers of our invention, there is a tendency towards decomposition when those compounds are aflected by certain stimuli Brimmss F" such as light, heat, or possibly the presence of impurities. Plasucizer 333113.011 15% R11.) When this occurs, it may become necessary that the maeii terial be subjected to some sort of a purification treat- ,gggg gg g ment prior to use unless some additive is employed to inhibit the deterioration. We have found that the addition of a minute amount of sodium diethylene dithiocar- 0 0. 24 o bamate to compositions containing poly(alkylene glycols) gor other alkylene glycol derivatives, acts to increase the N 0 0:22 0 stability of those compositions. We have found that it gj'ggf gfi f f acetate-m g is desirable to employ the sodium diethylene dithiocarbamate in the portion of 0.01% of the weight of the lycol to obtain an effective stabilizing action. Any pro- Certain film coatings are desensitized locally by strains g K produced in the emulsions by bending the sheets sharply gag g? igg fi gg g g g efiectwe such as up to or kinkin them. This so called kink desensitization s well knov vn and is a serious problem in handling large plastlc-lzmg m-atenals o? .0111- }nvenhon are espe- Sheets of some kinds of film for example X ray film The crally useful 111 gelatin compositions intended for photorollowing example illustrates the usefulness of the plasgraphic w i' We have founqtfihat i use thoie ticizers of our inventioninreducing kmk' "desensitization. glyco-l denvatlves m accord-awe W1 Rmmventlon suflicient amounts to effectively plasticrze photographic Example 11 emulsions at low humidities, does not cause any unde- Ahigh-speed panchromatic-sensitized gelatin silver hal- Sirable change? m physical or .sep.sltometnc Propel-fies ide emulsion was divided into several parts and treated even when sub ected to high humidltres and temperatures. as indicated below. 'The parts were coated ontoacellulose for example the (iblectlonable tickmess. tt acetate support, dried, exposed on an Eastman cessive softness characteristic of glycerin plast1c1z1ng 1s sitometer and processed withv the indicated results. The Obvlatedplasticizers used and the amounts employed plus the 9 The photographlc 6111111519118 used 111 practlcms 0111' 1 results of evaluation of the product were as follows: vention are of the developing-out type.

Sensltometrie results Wedge 1 Plastleizer bending Sward concentrasensirocker tion based tlvlty tackiness, Plasticizer on weight Rela- 70 F., test time of gelatin, tive Gamma Fog BE, in second percent film wedge avg.

speed opening 0150 in.

Glycerin 8 100 0.93 0.04 Bad 28 Triethylene glycol diacetate. 16 100 0.95 0.04 Medium. 27

1 The wedge bending sensitivity" is a measure of the tendency to show kink desensitization as the result of strains.

The Sward Rocker results show that the improved resistance to kink desensitization was obtained without any appreciable increase in softness or tackiness.

Example 12 The emulsions can be chemically sensitized by any of the accepted procedures. The emulsions can be digested with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard U.S. Patents 1,574,944 and 1,623,499, and Sheppard and Brigham 2,410,689.

The emulsions can also be sensitized with salts of the noble metals, as described in Smith and Trivelli U.S. Patent 2,448,060.

In Examples 11 and 12 the plasticizers of our invention were used in higher concentration than was the glycerin. Although glycerin would plasticize better in higher proportion, use of that higher concentration of glycerin is precluded because of the severe tackiness which occurs with the use of considerable amounts of glycerin. The plasticizers in accordance with our invention, however, can be used without introducing a tackiness problem.

Often in the use of poly(alkylene glycols) and the Patent 2,487,850, Lowe and The emulsions can also be chemically sensitized with gold salts as described in Waller and Dodd U.S. Patent 2,399,083 or stabilized with gold salts as described in Damschroder U.S. Patent 2,597,856 and Yutzy and Lecrmakers U.S. Patent 2,597,915.

. The emulsions can also be chemically sensitized with reducing agents such as those disclosed in Carroll U.S. Jones U.S. Patent 2,518,698;

9 Lowe and Allen U.S. Patent 2,521,925; and Lowe et al. U.S. Patents 2,521,926, 2,743,182, and 2,743,183.

The emulsions can also be optically sensitized with cyanine and merocyanine dyes, such as those described in Brooker US. Patents 1,846,301; 1,846,302; and 1,942,- 854; White U.S.Patent 1,990,507; Brooker and White U.S. Patents 2,112,140; 2,165,338; 2,493,747; and 2,739,- 964; Brooker and Keyes U.S. Patent 2,493,748; Sprague U.S. Patents, 2,5 03,776 and 2,519,001; Brooker and Heseltine U.S. Patent 2,666,761; Heseltine U.S. Patent 2,734,- 900; Van Lare U.S. Patent 2,739,141; and Kodak Limited British Patent 450,958.

The emulsions can also be stabilized with the compounds of Allen, Byers, and Murray U.S. Patent 2,728,- 663; Carroll and Murray U.S. Patent 728,664; Leubner and Murray U.S. Patent 2,728,665; Carroll U.S. Patent 2,716,062; Brooker and Stand U.S. Patent 2,131,038; Jones U.S. patent application Ser. No. 493,047; Trivelli and Smith U.S. Patents 2,566,245 and 2,566,263.

The emulsions may also contain the speed-increasing compounds of Carroll U.S. Patent 2,271,623; Carroll and Allen U.S. Patent 2,288,226; Carroll and Spence U.S. Patent 2,334,864; and Carroll and Beach U.S. Patent 2,708,162.

The emulsions can also contain plasticizing agents, such as glycerin or those described in Murray and Milton U.S. patent application Ser. No. 588,951; Milton U.S. patent application Ser. No. 662,564; Gates and Illingsworth U.S. patent application Ser. No. 527,872; Gray U.S. patent application Ser. No. 604,333; and Tong U.S. patent application Ser. No. 311,319. They may be added to the emulsion-before or after any sensitizing dyes which are used.

The emulsions can be hardened with formaldehyde or other gelatin hardeners, such as those described in White U.S. Patent 2,080,019; Allen and Carroll U.S. Patents 2,725,294 and 2,725,295; Allen and Byers U.S. Patent 2,725,305; Allen and Laakso U.S. Patent 2,726,162; July, Knott and Pollak U.S. Patent 2,723,316; Allen and Burness U.S. patent application Ser. No. 556,031; Allen and Webster U.S. patent application Ser. No. 599,891; and Jefireys U.S. patent application Ser. No. 624,968.

The emulsions can contain coating aids, such as saponin for those described in Knox and Davis U.S. Patent 2,719,- 087; Knox and Twardokus, U.S. Patent 2,739,891; Knox and Davis U.S. patent application Ser. No. 485,424; Wilson, Knox, and Stenberg U.S. patent application Ser. No. 485,812; Knox and Wright U.S. patent application Ser.

No. 556,055; Knox and Wilson U.S. patent application Ser. No. 600,679; and Knox and Stenberg U.S. patent application Ser. No. 691,125.

Various silver salts may be used as the sensitive salt, such as silver bromide, silver iodide, silver chloride, or mixed silver halides such as silver chlorobrornide or silver bromoiodide.

The agents of the instant application may be used in emulsions intended for color photography, for example, emulsions containing color-forming couplers or other materials that will generate color images, emulsions to be developed by solutions containing couplers or other colorgenerating materials, emulsions of the mixed packet type, such as described in Godowsky U.S. Patent 2,698,794, or emulsions of the mixed grain type, such as described in Carroll and Hanson U.S. Patent 2,592,243. These agents can also be used in emulsions which form latent images predominantly on the surface of the silver halide crystal or in emulsions which form latent images predominantly inside the silver halide crystal, such as those described in Davey and Knott U.S. Patent 2,592,250.

They may also be used in emulsions intended for use in silver halide solvent transfer processes, such as those described in Rott U.S. Patent 2,352,014; Land U.S. Patents 2,584,029, 2,698,236, and 2,543,181; and Y ackel et al. U. S. patent application Ser No. 586,705, or in color transfer processes, such as those described in Land U.S.

10 Patents 2,559,643, 2,698,798; Belgian Patents 554,933, 554,934, 554,935 and 554,212; Yutzy U.S. Patent 2,- 756,142; and Whitmore U.S. patent application Ser. No. 570,179.

The dispersing agent for thesilver halide may be gelatin or other colloidal material, such as collodion, albumin, celiulose derivatives or synthetic resins, for example, polyvinyl compounds. Some of the colloids that may be used are described in Lowe U.S. Patent 2,286,215; Lowe and Clarke U.S. Patent 2,327,808; Lowe, Minsk, and Kenyon U.S. Patent 2,541,474; Lowe U.S. Patent 2,563,791, Unruh and Smith U.S. Patent 2,768,154; and Unruh et al. U.S. Patent 2,808,331. Compatible mixtures of two or more of these colloids may be used.

In addition, combinations of these antifoggants, sensitizers, hardeners, etc., may be used.

We claim:

1. As a composition of matter adapted for use in making photographic products a homogeneous mixture of gelatin and 5-30%,' based on the weight of the gelatin, of a -3 00 molecular weight plasticizer compound having the formula:

in which R is a radical selected from the group consisting of alkyl and acyl, R is an alkylene-radical, R is alkyl and n is a simple integer from 1 to 8.

2. As a coating composition adapted for use in making photographic products an aqueous solution of a mixture of gelatin and 5-30%, based on the weight of the gelatin, of a 100-300 molecular weight plasticizer compound having the formula:

in which R, is a radical selected from the group consisting of alkyl and acyl, R is an alkylene radical, R is alkyl and n is a simple integer from 1 to 8.

3. A silver halide photographic emulsion in which the carrier for the silver halide essentially consists of an aqueous solution of a mixture of gelatin and 530%, based on the weight of the gelatin, of a 100-300 molecular weight plasticizer compound having the formula:

in which R is a radical selected from the group consisting of alkyl and acyl, R is an alkylene radical, R is alkyl, and n is a simple integer from 1 to 8.

4. As a composition of matter a homogeneous mixture of gelatin and 530%, based on the weight of the gelatin, of methoxy triglycol acetate as the plasticizer for the gelatin.

5. As a composition of matter a homogeneous mixture of gelatin and 5-30%, based on the weight of the gelatin, of glycol diacetate as the plasticizer for the gelatin.

6. As a composition of matter a homogeneous mixture of gelatin and 5-30%, based on the weight of the gelatin, of triethylene glycol diacetate as the plasticizer for the gelatin.

7. As a composition of matter a homogeneous mixture of gelatin and 530%, based on the weight of the gelatin, of 2-(2-methoxyethoxy) ethylacetate as the plasticizer for the gelatin.

8. As a composition of matter a homogeneous mixture of gelatin and 5-30%, based on the weight of the gelatin, of 2-methoxy ethylacetate as the plasticizer for the gelatin.

the carrier for the silver halide essentially consists of anaqueous solution of a mixture of gelatin and 5-30% based on the Weight of the gelatin, of methoxy triglycol acetate as the plasticizer for the gelatin.

References Cited in the file of this patent UNITED STATES PATENTS Marines et a1. Dec. 15, Mannes et a1. Dec. 15, Jelley et a1. June 15, V Loder Oct. 30, Morgan et al. Jan. 24, Moessen July 31, 

1. AS A COMPOSITION OF MATTER ADAPTED FOR USE IN MAKING PHOTOGRAPHIC PRODUCTS A HOMOGENEOUS MIXTURE OF GELATIN AND 5-30%, BASED ON THE WEIGHT OF THE GELATIN, OF A 100-300 MOLECULAR WEIGHT PLASTICIZER COMPOUND HAVING THE FORMULA: 